Loran Station Research Articles

Metric and Upper Dimension of Extended Annihilating-Ideal Graphs

The metric dimension problem is called navigation problem due to its application to robot navigation in space. Further this concept has wide applications in motion planning, sonar and loran station, and so on. In this paper, we study certain results on the metric dimension, upper dimension and resolving number of extended annihilating-ideal graph [Formula: see text] associated to a commutative ring [Formula: see text], denoted by [Formula: see text], [Formula: see text] and [Formula: see text], respectively. Here we prove the finiteness conditions of [Formula: see text] and [Formula: see text]. In addition, we characterize [Formula: see text], [Formula: see text] and [Formula: see text] for artinian rings and the direct product of rings.

Cold War conflicts and the USCG Afetna Point LORAN station in Saipan, CNMI

ABSTRACT This study focuses on the US Coast Guard LORAN station at Afetna Point in Saipan, Commonwealth of the Northern Mariana Islands, to discern what social impact the Cold War facility and servicemen had on the local community. Archaeological and archival investigations indicate that the facility was built a few months after the American WWII invasion of Japanese-held Saipan in June 1944. Oral histories gathered from senior members of the indigenous Chamorro community in the village of San Antonio revealed that the station and US Coast Guard service members played a complex and vital role in the social and economic life of the local community during the Cold War.

Fault-Tolerant Metric Dimension of Interconnection Networks

A fixed interconnection parallel architecture is characterized by a graph, with vertices corresponding to processing nodes and edges representing communication links. An ordered set <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> of nodes in a graph <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G$ </tex-math></inline-formula> is said to be a resolving set of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G$ </tex-math></inline-formula> if every node in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G$ </tex-math></inline-formula> is uniquely determined by its vector of distances to the nodes in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> . Each node in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> can be thought of as the site for a sonar or loran station, and each node location must be uniquely determined by its distances to the sites in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> . A fault-tolerant resolving set <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> for which the failure of any single station at node location <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$v$ </tex-math></inline-formula> in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> leaves us with a set that still is a resolving set. The metric dimension (resp. fault-tolerant metric dimension) is the minimum cardinality of a resolving set (resp. fault-tolerant resolving set). In this article, we study the metric and fault-tolerant dimension of certain families of interconnection networks. In particular, we focus on the fault-tolerant metric dimension of the butterfly, the Benes and a family of honeycomb derived networks called the silicate networks. Our main results assert that three aforementioned families of interconnection have an unbounded fault-tolerant resolvability structures. We achieve that by determining certain maximal and minimal results on their fault-tolerant metric dimension.

ELoran: Resilient Positioning, Navigation, and Timing Infrastructure in Maritime Areas

Global navigation satellite system (GNSS) and localization technology have become highly compact and effective. Although GNSS has been proven to be vulnerable to jamming when the signal strength is weak, most vehicles rely on it for navigation. Compared to GNSS, enhanced Loran (eLoran) is more resistant to jamming and is recommended as a realistic alternative to GNSS. Therefore, South Korea embarked on an eLoran testbed development project to provide resilient navigation information for maritime users. The primary goal of this project was to demonstrate that the system can provide a 20-m position accuracy to the maritime user within a 30-km coverage of a differential Loran station. In this paper, we describe the development of the eLoran testbed implementation and the performance of its preliminary experimental results. To confirm the feasibility of the eLoran testbed performance, we installed an eLoran transmitter and two differential Loran stations and subsequently conducted a zero-baseline performance test at the Pyeongtaek differential Loran station with a new eLoran signal. We also conducted a survey to collect conventional Loran signals along the western and southern coastlines of South Korea. Our experimental results show that the eLoran system met the performance requirements of this project, as well as that the signal to noise ratio of the eLoran signals changed over the topographic characteristics of the propagation path.

A statistical and spatial analysis of chemical contaminants in Cocos Lagoon, Guam

Cocos Lagoon is located on the southwestern end of the coast of Guam, and contains extensive coral reefs and an array of fish species. Within the Lagoon is a former US Coast Guard LORAN station on Cocos Island. Hazardous materials appear to have been disposed of on land and in near shore waters during the operation of the LORAN station, between the years of 1944 and 1963, exposing surrounding waters, sediment, fish species and humans to these materials. As part of a project to quantify chemical contaminants in Cocos Lagoon, and to address local and agency human health concerns, approximately 190 chemical contaminants were analyzed in sediments from 25 sites, along with 27 fish tissue samples from 16 sites. Higher levels of chemical contaminants were found in fish tissues collected from around Cocos Island, the site of the former LORAN station. Concentrations of polychlorinated biphenyls (PCBs), for example, were above an EPA recreational fishers’ screening value (SV) in some fish species from around Cocos Island, indicating risk to humans consuming fish from this area. PCBs at high concentrations are known to cause negative effects on resident marine aquatic organisms and human health concerns include cancer. Characterizing contaminant impacts to aquatic marine organisms and possible human health results from this project will provide resource managers with key information needed to make effective decisions for the health of Cocos Lagoon and also gauge the efficacy of restoration activities. The results show high levels of PCBs in the fish species from Coco Lagoon. This indicates that there is a high risk of adverse health effects such as cancer if consumed by humans.

포항 로란-C 송신 신호의 기준위상 오프셋 측정

In order to establish eLoran (enhanced Long Range Navigation) system, it needs the advancement of receiver, transmitter, data channel addition for Loran information, differential Loran sites for compensating Loran-c signal and ASFs (Additional Secondary Factors) database, etc. In addition, the precise synchronization of transmitting station to the UTC (Coordinated Universal Time) is essential if Loran delivers the high absolute accuracy of navigation demanded for maritime harbor entrance. For better timing synchronization to the UTC among transmitting stations, it is necessary to measure and monitor the transmission delay of the station, and the correction information of the transmitting station should be provided to the user's receivers. In this paper we presented the measurement method of absolute delay of Pohang Loran transmitting station and developed a time delay measurement system and a phase monitoring system for Loran station. We achieved -2.23 us as a result of the absolute phase delay of Pohang station and the drift of Loran pulse of the station was measured about 0.3 us for a month period. Therefore it is necessary to measure the delay offset of transmitting station and to compensate the drift of the Loran signal for the high accuracy application of PNT (Positioning, Navigation and Timing).

Improving Loran Coverage with Low Power Transmitters

Enhanced Loran (eLoran) is currently being implemented to provide back up to global navigation satellite systems (GNSS) in many critical and essential applications. In order to accomplish this, eLoran needs to provide a high level of availability throughout its desired coverage area. While the current Loran system is generally capable of accomplishing this, worldwide, there remain a number of known areas where improved coverage is desirable or necessary. One example is in the middle of the continental United States where the transmitter density is not adequate for providing the desired availability for applications such as aviation in some parts. This paper examines the use of lower power, existing assets such as differential GPS (DGPS) and Ground Wave Emergency Network (GWEN) stations to enhance coverage and fill these gaps. Two areas covered by the paper are the feasibility and performance benefits of using the antennas at these sites.Using DGPS, GWEN or other existing low frequency (LF) broadcast towers requires the consideration of several factors. The first is the ability of the transmitting equipment to efficiently broadcast on these antennas, which are significantly shorter than those at a Loran station. Recent tests at the US Coast Guard Loran Support Unit (LSU) demonstrated the performance of a more efficient transmitter. This technology allows for the effective use of smaller antennas at lower power levels. Second is the ability to broadcast a navigation signal that is compatible with the Loran system and the potential DPGS broadcast (when using a DGPS antenna). The paper examines some possibilities for navigation signals. The goal is to develop a suitable low power signal that enhances navigation and is feasible for the transmission system.The second part of the paper examines the benefits of using these stations. The benefits depend on the location of the stations and the ability seamlessly to integrate them within the existing Loran infrastructure. Analysis of these factors is presented and the coverage benefits are examined.

Loran-C Chain and UTC Synchronisation

There has been much discussion recently implying that Loran-C chain synchronisation using ‘System Area Monitor’ (SAM) control and using ‘Time of Transmission (or Emission)’ (TOT or TOE) are incompatible mechanisations of Loran-C chain time management because of their differing impact on users. Further, the mechanisation of UTC synchronisation is described as either satellite (GPS/GLONASS) based or Loran Chain measurement based, thereby excluding integrated use of both techniques for reliability. These differences are not mutually exclusive. Well-defined chain synchronisation can logically apply all measurement and control techniques as well as providing improved accuracy. This paper defines synchronisation and describes the history of Loran-C synchronisation control and the current methods employed. The existence of Cesium Standards at Loran stations, and the recent introduction of digital signal processing receivers, have greatly changed the potential for extremely precise timing control, detection of extraordinary timing changes, and the maintenance of very tight UTC synchronisation. This paper describes a number of techniques for defining, observing and applying the various sources of timing information, optimising performance for users and simplifying implementation for service providers.

Combining Pseudoranges from GPS and Loran-C for Air Navigation

User equipment that combines pseudoranges from GPS and Loran would be more reliable than an unaided GPS receiver or a Loran-only receiver. It could remove coverage outages caused by satellite shutdowns and/or bad satellite geometry. Similarly, it could remove most of the coverage outages caused by Loran station shutdowns, high atmospheric noise levels, or precipitation static. A hybrid GPS/Loran receiver could also reliably provide self-contained fault detection and isolation (otherwise known as receiver autonomous integrity monitoring, or RAIM). This paper treats position fixing, receiver autonomous fault detection, and receiver autonomous fault isolation as system services, and computes the probability of outage for these three services. Our analysis computes the outage probability for the level of service required for nonprecision approach and en route navigation in the National Airspace System. It assumes that GPS is configured in the Optimal 21 Satellite Constellation, and includes the effects of satellite as well as Loran station shutdowns. Finally, our analysis examines whether it is important to synchronize Loran transmissions to GPS time.

ATTACKING VOLTAGE FLUCTUATIONS WITH SOLID STATE ELECTRONICS

Naval Engineers JournalVolume 86, Issue 1 p. 77-83 ATTACKING VOLTAGE FLUCTUATIONS WITH SOLID STATE ELECTRONICS CDR. DAVID B. FLANAGAN USCG, CDR. DAVID B. FLANAGAN USCG The author graduated from the U.S. Coast Guard Academy in 1955 and served three years aboard USCGC Mackinac as Navigator, Operations Officer, Damage Control Assistant, and student Engineer. After a 13 months tour as Commanding Officer, USCG Loran Station, Pusan, Korea, he entered Massachusetts Institute of Technology from which he received his Professional degree as Naval Engineer and his Masters degree in Marine Engineering in 1962. He then served as Engineer Officer, USCGC Eastwind, participating in Operation Deep Freeze for two years after which he was assigned to the U.S. Coast Guard Academy in 1964 where he taught various engineering subjects until completing his tour as Chief of the Electrical Engineering Section. He was next assigned to U.S.C.G. Headquarters in 1968 as Project Officer on the design of a high endurance oceanographic ship, and subsequently as Chief of the High Endurance Cutter Section in the Shipbuilding and Maintenance Branch. He is a registered Professional Engineer in the State of Connecticut, and at present is the Chief of the Naval Engineer-Branch, ELEVENTH Coast Guard District, Long Beach, California.Search for more papers by this author CDR. DAVID B. FLANAGAN USCG, CDR. DAVID B. FLANAGAN USCG The author graduated from the U.S. Coast Guard Academy in 1955 and served three years aboard USCGC Mackinac as Navigator, Operations Officer, Damage Control Assistant, and student Engineer. After a 13 months tour as Commanding Officer, USCG Loran Station, Pusan, Korea, he entered Massachusetts Institute of Technology from which he received his Professional degree as Naval Engineer and his Masters degree in Marine Engineering in 1962. He then served as Engineer Officer, USCGC Eastwind, participating in Operation Deep Freeze for two years after which he was assigned to the U.S. Coast Guard Academy in 1964 where he taught various engineering subjects until completing his tour as Chief of the Electrical Engineering Section. He was next assigned to U.S.C.G. Headquarters in 1968 as Project Officer on the design of a high endurance oceanographic ship, and subsequently as Chief of the High Endurance Cutter Section in the Shipbuilding and Maintenance Branch. He is a registered Professional Engineer in the State of Connecticut, and at present is the Chief of the Naval Engineer-Branch, ELEVENTH Coast Guard District, Long Beach, California.Search for more papers by this author First published: February 1974 https://doi.org/10.1111/j.1559-3584.1974.tb03572.x AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume86, Issue1February 1974Pages 77-83 RelatedInformation

Use of Loran in the Range-Range Mode*

A method foe synchronizing a remote clock with transmissions from a loran station is discussed. The method is essentially a programming technique and permits improved position-fixing accuracies by the use of a range-range mode of navigation. The times of arrival of pulses from three stations are measured at the observed position and the time of transmission is estimated. Two pairs of estimated ranges are used to compute the user's position. The estimated time of transmission is varied until the two calculated positions coincide; consequently, the clock is synchronized with the loran chain. The effect of receiver instrument error on the accuracy of computing the time of transmission and the effect of propagation anomalies on different types of position fixes are discussed.

MODEL TESTING IN ICE

Naval Engineers JournalVolume 80, Issue 2 p. 259-264 MODEL TESTING IN ICE LIEUTENANT COMMANDER G. P. VANCE, LIEUTENANT COMMANDER G. P. VANCE USCG THE AUTHOR: was graduaed from the U. S. Coast Guard Academy in June 1957 with a Bachelor of Science Degree and an Ensign's Commisison in the U. S. Coast Guard. His first assignment was a weather patrol ship operating in the North Atlantic. He first served as a deck officer; later as an engineering watch officer. The period from 1960 to 1961 was spent as Commanding Officer of Ulithi Loran Station in the South Pacific. The period from 1961 to 1963 was spent at the University of Michigan in pursuit of a Master of Science Degree in Naval Architecture, Marine Engineering and Nuclear Engineering. Upon graduation from Michigan, LCDR Vance served as engineering officer aboard the Coast Guard icebreaker WESTWIND until 1965, when he was transferred to Coast Guard Headquarters to work on the design of a new Coast Guard polar icebreaker. LCDR Vance is a member of the American Society of Naval Engineers and a Registered Professional Engineer in the state of Michigan.Search for more papers by this author LIEUTENANT COMMANDER G. P. VANCE, LIEUTENANT COMMANDER G. P. VANCE USCG THE AUTHOR: was graduaed from the U. S. Coast Guard Academy in June 1957 with a Bachelor of Science Degree and an Ensign's Commisison in the U. S. Coast Guard. His first assignment was a weather patrol ship operating in the North Atlantic. He first served as a deck officer; later as an engineering watch officer. The period from 1960 to 1961 was spent as Commanding Officer of Ulithi Loran Station in the South Pacific. The period from 1961 to 1963 was spent at the University of Michigan in pursuit of a Master of Science Degree in Naval Architecture, Marine Engineering and Nuclear Engineering. Upon graduation from Michigan, LCDR Vance served as engineering officer aboard the Coast Guard icebreaker WESTWIND until 1965, when he was transferred to Coast Guard Headquarters to work on the design of a new Coast Guard polar icebreaker. LCDR Vance is a member of the American Society of Naval Engineers and a Registered Professional Engineer in the state of Michigan.Search for more papers by this author First published: April 1968 https://doi.org/10.1111/j.1559-3584.1968.tb04509.xCitations: 2 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume80, Issue2April 1968Pages 259-264 RelatedInformation

The Introduction, Increase, and Crash of Reindeer on St. Matthew Island

Reindeer (Rangifer tarandus), introduced to St. Matthew Island in 1944, increased from 29 animals at that time to 6,000 in the summer of 1963 and underwent a crash die-off the following winter to less than 50 animals. In 1957, the body weight of the reindeer was found to exceed that of reindeer in domestic herds by 24 53 percent among females and 46 61 percent among males. The population also responded to the high quality and quantity of the forage on the island by increasing rapidly due to a high birth rate and low mortality. By 1963, the density of the reindeer on the island had reached 46.9 per square mile and ratios of fawns and yearlings to adult cows had dropped from 75 and 45 percent respectively, in 1957 to 60 and 26 percent in 1963. Average body weights had decreased from 1957 by 38 percent for adult females and 43 percent for adult males and were comparable to weights of reindeer in domestic herds. Lichens had been completely eliminated as a significant component of the winter diet. Sedges and grasses were expanding into sites previously occupied by lichens. In the late winter of 196364, in association with extreme snow accumulation, virtually the entire population of 6,000 reindeer died of starvation. With one known exception, all of the surviving reindeer (42 in 1966) were females. The pattern of reindeer population growth and die-off on St. Matthew Island has been observed on other island situations with introduced animals and is believed to be a product of the limited development of ecosystems and the associated deficiency of potential populationregulating factors on islands. Food supply, through its interaction with climatic factors, was the dominant population regulating mechanism for reindeer on St. Matthew Island. St. Matthew Island, 128 square miles in area and located in the Bering Sea Wildlife Refuge in the north central Bering Sea (Fig. 1), supports a poorly developed land fauna. Native land mammals are restricted to a vole (Microtus abbreviatus) and the arctic fox ( Alopex lagopus ), although a resident population of polar bears (Thalarctos maritimus) existed there in Recent times (Elliot 1882). The reindeer on St. Matthew Island were the result of the release of 24 females and 5 males on August 20, 1944, by the U. S. Coast Guard (Klein 1959). Shortly afterwards, the Coast Guard loran station on the island was abandoned and the island has been uninhabited since then. Specimens taken for study purposes and those shot by Coast Guard personnel as a recreational pursuit have been the only harvest from the herd. With the exception of 10 in 1966, these were all taken during 1957-63 and totaled 105 animals. This paper reports on the population dynamics and range interrelationships of this island reindeer herd from the time of introduction through its rapid increase and crash die-off until July, 1966. I appreciate the field cooperation of colleagues Dr. Francis H. Fay, Dr. Vernon L. Harms, Jack Manley, and Gerry Cowan and the assistance of James Whisenhant and Dr. Detlef Eisfeld. Dr. Eisfeld also did the analyses of the reindeer ovarian material and, through discussion, provided useful suggestions for the interpretation of the data. Sam Harbo provided advice in the statistical treatment of data.

本邦近海におけるデツカとロランAの勢力分布図について(日本航海学会第39回講演会)

First, I drew the contours of constant probability density of Decca fixes in the adjacent waters of Hokkaido and Kyushu, using the "probaaility density formulae." Secondly, by comparing these of Loran fixes with the abovementioned contours, I tried to make a practical chart of Loran and Decca coverages, with which navigators could select the appropriate chain and pair of the Decca system or the triplet of Loran stations to obtain the most accurate fix in the ditto waters in daytime and at night.

The reception of ground-based Loran transmissions by the fixed-frequency topside sounder satellite

Transmissions from ground-based Loran stations have frequently been detected by the 2 MHz receiver on the Explorer 20 satellite; the form of the resultant interference permits the identification of individual Loran transmitters. A statistical study of the occurrence of the interference on passes recorded at Winkfield in the United Kingdom suggests that it is due to an E-W trough of low critical frequency at latitudes between about 55°N and 65°N at western European longitudes; this trough may be associated with the trough of low electron density observed over Canada by Muldrew.

Structure and Movement of Es Detected by Loran Observations

A study is made of movements in the Es region by means of measurements of pulsed waves at 1.85Mc/s emitted from a Loran station and of ionospheric vertical soundings.Moving clouds in the Es region of large lateral dimensions are usually observed during the night either isolated or grouped like the wavy clouds sometimes seen in the troposphere. The speed of about 80m/sec and the direction towards the southwest are deduced from various kinds of observations.It is inferred from this experiment that the observed Es layer is of two types: the first is the horizontally stratified thin layer produced by electromagnetic re-distribution due to the laminar wind shear and the second consists of a number of elongated regions of excess ionization, being of the order of 100km long and 10km wide, which may be caused by hydrodynamical instability in the wind shear prevailing there.

ロラン受信機におけるLodar方式の可能性について(日本航海学会第28回講演会)

It is very difficult to determine the position of a ship at a point near the coast or others when it can clearly receive the waves transmitted from a pair of station but cannot receive well those from another pair, or when the hyperbolic line of position (LOP) is widely spread out. In regard to such cases, we made an experimental test on a practicability of obtaining the position by using the Loran receiver as the Lodar to determine the bearing line of the master or slave station and finding its intersecting point with the hyperbolic LOP of the pair of station. As a result, we found the following facts. 1. Lodar method is successfully applicable when visibility is limited, namely at a cloudy or rainy weather or when the land is covered with gas or mist and surveying is impossible, or at a point near the coast where it is difficult to determine the position of the ship by hyperbolic LOP. 2. In such cases at night, measurement by Lodar method seems to be of higher accuracy than by sky waves transmitted from a pair of station. 3. As the Lodar is highly sensitive, relative bearing is easily obtained, but on account of rolling of the ship it was difficult to determine it at one time of measurement. We measured six or eight times and took the mean value. 4. It seems that the error becomes larger as the angle between the hyperbolic LOP and the Loran bearing line gets sharper (namely, as it enters into, what is called, back side of the Loran station).

TORQUE MEASUREMENTS ON ROTATING SHAFTS

Naval Engineers JournalVolume 74, Issue 4 p. 697-710 TORQUE MEASUREMENTS ON ROTATING SHAFTS LIEUTENANT DAVID B. FLANAGAN, LIEUTENANT DAVID B. FLANAGAN USCG The author graduated from the Coast Guard Academy in 1955 and served three years aboard the Coast Guard Cutter MACKINAC operating in the North Atlantic. He completed engineering training aboard the MACKINAC qualifying him to serve as an engineering officer. He served as Commanding Officer of the Coast Guard Loran Station in Pusan, Korea. He was recently engaged in study at MIT in Cambridge, Mass., in the Marine Engineering department. He was graduated in June at which time he reported to the icebreaker, EASTWIND, to serve as assistant engineering officer.Search for more papers by this author LIEUTENANT DAVID B. FLANAGAN, LIEUTENANT DAVID B. FLANAGAN USCG The author graduated from the Coast Guard Academy in 1955 and served three years aboard the Coast Guard Cutter MACKINAC operating in the North Atlantic. He completed engineering training aboard the MACKINAC qualifying him to serve as an engineering officer. He served as Commanding Officer of the Coast Guard Loran Station in Pusan, Korea. He was recently engaged in study at MIT in Cambridge, Mass., in the Marine Engineering department. He was graduated in June at which time he reported to the icebreaker, EASTWIND, to serve as assistant engineering officer.Search for more papers by this author First published: November 1962 https://doi.org/10.1111/j.1559-3584.1962.tb05404.x AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume74, Issue4November 1962Pages 697-710 RelatedInformation

Loran-C: A Precision Radionavigation System

LORAN-C IS A HYPERBOLIC system of radionavigation, similar to Loran-A, which can be used by ships and aircraft for position fixing in all weather, on the sea as well as over land. It operates in the frequency band of 90–110 kilocycles, which was allocated for long-distance radionavigation systems by the, 1947 International Telecommunications Union Conference (ITU). The first Loran-C throe-station chain (triad) was implemented on the United States cast coast in 1957. Since that time much useful information has been learned about the system by employing ships and planes on probing trips into the service area. Results indicate that the system can unquestionably provide high-accuracy, long-distance radionavigation service. The United States Coast Guard is now looking toward dual-frequency capabilities wherein a single Loran station will transmit both Loran-A and Loran-C signals. Then, if it appears timely in the future, it would be possible to gradually discontinue the Loran-A operation with Loran-C remaining as a single, precision, long-range radionavigation system.

ローランに於ける空間波の伝播誤差特性 : I. 観測結果とPierce's Equatinとの比較(日本航海学会第15回講演会)

The characteristics of Loran sky wave propagation errors is very important in order to determine the probable errors of Loran fix using the sky wave. These errors near the Japan area are evaluated by measuring the Loran sky wave time differences from each Loran station to the fixed receiving position and compared with the Pierce's equation. Observed results are shown in the figures representing the relation between the relative number of observation and the sky wave reading. By Pierce's equation, the probable errors of sky wave delay are depend on the distance between the Loran station and the receiving position. So the errors of sky wave reading depend upon the both distances from the master and slave station to the receiving position. We propose the equivalent distance by which the errors are decided. The errors, however, are also the function of the base line length. We can decide these errors by the equivalent distance and the base line length. The probable errors of Loran sky wave propagation calculated from the observed results are shown in the figures as the functions of the equivalent distance and the base line length, and one can see that these results are considerably agree with the Pierce's equation.